Ecological assessment of phytoplankton community via microscopic method and 18S rRNA gene sequencing in Pearl River Estuary

¹ Guangzhou Institute of Geochemistry, Chinese Academy of Scineces, 511 Kehua Road, Guangzhou 510640, China
² Guangdong Province Vocational School of Oceanographic Engineering, 15 Chisha Road, Guangzhou 510320, China
³ State Environmental Protection Key Laboratory of Urban Ecological Environment Simulation and Protection, South China Institute of Environmental Sciences, MEE, 18 Ruihe Road, Guangzhou 510535, China

^* Corresponding author: chenchen7@scies.org
^‡ These authors contributed equally to this work and should be regarded as co-first authors.

Abstract

Monitoring phytoplankton community underpins our understanding of water quality and ecological functions. In this study, we approached phytoplankton abundance, community composition, and diversity by both microscopy and 18S rRNA gene sequencing. Environmental variances influencing the phytoplankton were evaluated as well. There were 6 phyla and 62 species identified by microscopy, and the diversity index Shannon-Wiener and evenness index Pielou index indicated phytoplankton community had high diversity; however, the high density of dominance genus suggested that our research region had potential red tide effects. The canonical correspondence analysis illustrated that suspended solids, phosphate and temperature were three major factors that affected the distribution and components of phytoplankton community. The DNA barcoding sequencing of 18S rRNA gene supported the main results via microscopic methods while providing more identified community components, which implied that 18S rRNA gene sequencing can be used as a supplemental method for fast ecological assessment of phytoplankton community.